Perry g



P. G. GARDINER.

Car Spring.

Patented N0v. 2, 1858,

L n 1 Fr Z92 9 MI C/ ".FEIERS, PHOm-u'moGRAPuER. WASHINGTON, 11C.

man r as raranr rare PERRY G. GARDINER, OF NEYV YORK, N. Y.

CAB-SPRING.

To all whom it may concern:

Be it known that I, PERRY G. GARDINER, of the city of New York, N. Y., mechanical engineer, have invented certain new and useful improvements in the conical coiled steel springs for use in railroad-cars and applicable to other purposes where springs of great strength and elastic power are required, and that the following is a full and exact description of my said improvements and of the construction of the same, reference be ing had to the drawings accompanying and making part of this my specification.

Figure 1. represents the steel plate of which the spring is made. Fig. II. is an elevation of the spring standing upon its base. Fig. 111. represents a view of the interior of the spring as seen from the base. Fig. IV. a vertical cross section through the center of the spring.

Heretofore in constructing steel coiled conical springs, for railroad cars, the bar or plate of which it is formed has been made thinner or narrower and sometimes both, toward that part of the plate which constitutes the smaller coils or apex of the spring. This has been thought necessary, in order to equalize the elasticity of the smaller coils, or those having the shorter leverage, with the larger coils or those having a longer leverage toward the base of the spring and for other purposes. This form of the plate, however, tends to diminish the strength of the spring, inasmuch as there is thereby given a less amount of metal and resisting force in one part of the spring than the other, while the weight or pressure upon all parts of the spring is the same, and it often causes the upper or smaller coils to yield first to the weight or pressure, and these parts being thus weaker, are apt to be deficient in elastic power, or to break altogether, and thus materially affect the strength, and efiiciency of the spring.

I constructmy spring of an oblong plate of steel as shown in Fig. I. of uniform thickness from end to end, and of uniform width, except that at the ends on opposite sides, a very acute angular piece is cut from the plate (as shown at a, a, Fig. I.) so that when the plate is coiled into a spring the top and base will be in horizontal planes, parallel to each other, and this gives the spring at top and bottom an even bearing all around. This plate thus formed, is then heated to a welding heat, and is placed upon a mandrel with a cylindrical stem and of the size and spiral form which the spring to be produced requires; the end of the plate constituting the apex of the spring being inserted into a slot in the straight part or cylindrical stem of the mandrel; the plate is then turned or coiled upon the mandrel and spiral cone, by machinery suited to the purpose (but not by hammering or rolling) so that the plate which being thus formed into the spring will be held close and evenly to the mandrel and cone, and thus make each coil uniform and equidistant the one from the other, with an open and circular center. By making the coils uniform and equally apart the one from the other, the spring when placed in the bath or fluid for tempering (as it must be after coiling) receives an equal amount of temper throughout every part, and thus has an uniform elasticity. In springs coiled in the manner heretofore practiced, in consequence of the difference in the thickness or quality of metal in different parts of the plate, and the unequal spaces between the coils the spring in some parts would be tempered too much and in other parts too little, and when subjected to pressure would break or bend.

The uniform thickness of the plate used by me and the uniformity of the spaces be tween the coils, renders the tempering uniform in all the parts of the spring; and also avoids any friction in the action of the spring.

Heretofore in making the coils of the spring it has been the practice to fasten the spring at the end to the mandrel by a slot cut at the end of the plate which was held by a button or cone upon the mandrel; this rendered the spring ditficult of removal from the mandrel, and also weakened the part of the spring so slotted. The plate has been also sometimes fastened to the mandrel by a. collar and cotter the end of the plate being hammered or flattened out to receive the key.

In the plate used by me, as above described, it is not necessary to slot or cut or hammer or otherwise mutilate the plate; and for the purpose of holding the plate firmly in the slot of the mandrel made to receive it, and to allow the first turn of the mandrel to give the plate the very short turn required without breaking, I nick or compress the plate of steel Z), Z), Fig. 1. across its face, without cutting or breaking the fiber of the metal, at the time when the edge of the slot in the mandrel takes hold of the plate at the first turn; and then in disengaging the coil from the mandrel, the part which was in the slot, comes ofi" or remains in a uniform coil With the rest of the spring, so that the center of the spring is an open and even space, to receive the bolt or boss for holding the spring when in position. I therefore claim as my invention the following nained improvements and features in the conical coiled steel spring, viz:

1. Its construction out of a plate or bar 7 P. G. GARDINER.

Witnesses I. B. STAPLES,

GEORGE XV. FOX. 

